There is a general belief by those skilled in the art of polymer supported catalysis that all types of polystyrene resins (macroreticular or gel) are inherently thermally unstable both in the presence or absence of oxygen. The upper temperature limit often cited for use of these catalyst-resin systems is quoted at approximately 150.degree. C. See Sherrington "Polymer Supported Reactions in Organic Synthesis"; Chap. 1 p. 27; Wiley: New York, 1980; See also: International Workshop on Heterophase Attached Homogeneous Catalysis, Grenoble, France, 1977 (CNRS and NSF) and Chauvin et al, "Polymer Supported Catalysts" Prog. Polymer Sci., Vol. 5, p. 100, Pergamon Press, (1977). The present innovation is concerned with functionalized macroreticular polystyrene that has utility as a catalyst for vapor phase Fischer-Tropsch reactions at temperatures in excess of 200.degree. C.
The use of a catalytic complex containing an anthranilic acid ligand for catalytic hydrogenation is disclosed in U.S. Pat. No. 3,755,194 to Avilov et al, issued Aug. 28, 1973. The Avilov patent relates to a homogeneous catalytic system for the hydrogenation of unsaturated compounds at room temperature and one atmosphere of hydrogen pressure. In this procedure a rhenium (I) complex of N-phenylanthranilic acid is employed. However, this procedure like other homogeneous catalytic systems has the disadvantage that it is difficult to separate the hydrogenation product from the catalyst itself with the result that the catalyst is a contaminant or an impurity in the final product.
Substituted phosphines have been used to chemically link a catalyst metal to a polymer support. Examples of this are found in Grubbs et al, "Polymer Preprints," American Chemical Society, Division Polymer Chemistry, 1972, Vol. 13, No. 2, pages 828-832 [Chem. Abs. Vol. 81, 6555d (1974)] and also Grubbs et al, "J. Macromol. Sci Chem.," 1973, Vol. 7, No. 5, Pages 1047-1063, [Chem. Abs. Vol. 78, 164622r (1973)].
U.S. Pat. No. 4,230,633 discloses polymer supported metal complexes wherein the ligand is a cycloalkadienyl radical with metals from Group VIII of the Periodic Table. This patent is concerned with the conversion of carbon monoxide and hydrogen to hydrocarbons in a liquid reaction medium.
U.S. Pat. No. 4,292,415 discloses a crosslinked polystyrene with cycloalkadienyl ligands and Group VIII metal carbonyls having utility as a Fischer-Tropsch catalyst in liquid phase reactions. This patent does not suggest the critical relationships that the present invention is concerned with, nor the specific ligands and vapor phase reactions.
Fischer-Tropsch catalysis by polystyrene supported cyclopentadienyldicarbonyl cobalt (CpCo(CO).sub.2) has been reported by Benner et al, (American Chemical Society Symposium Series 152 (1981) p. 165. The reaction was conducted in a medium pressure glass and stainless steel reactor. Benner et al suspended .circle.P --CpCo(CO).sub.2 in purified n-octane to swell the resin and allow access to catalyst sites in the interior of the beads; no detectable reaction took place if the solvent was excluded. This is in contrast to the present invention in which the reaction takes place in the vapor phase without the requirement that the polymer be swollen.
U.S. Pat. No. 4,323,698 discloses a weak base anion exchange resin which has been contacted with a solution of a coordination compound having at least two ligands connected to at least one central metal atom, to chemically bond the resin to the metal atom by replacement of at least one of the ligands of the coordination compound by a functional group of the weak base anion exchange resin. The complex can be used as a catalyst for hydrogenation, carbon monoxide insertion, polymerization, isomerization, vinyl ester exchange and ethylene oxidation reactions among others.
U.S. Pat. No. 4,144,191 discloses amine resins loaded with bimetallic clusters as novel hydroformylation catalysts. This patent is directed to the conversion of liquid olefins to alcohols in a one-step hydroformylation process which consists of contacting an olefin, such as 1-hexene in the liquid phase, with a gaseous mixture of carbon monoxide and hydrogen and the presence of a catalyst prepared by loading a bimetallic cluster onto an amine resin.
U.S. Pat. No. 4,238,358 discloses the use of anthranilic acid as a ligand for rhodium, palladium, platinum and ruthenium complexes. These catalysts are disclosed as reduction catalysts for liquid phase reactions, i.e. the hydrogenation of olefinic and aromatic hydrocarbons.
The prior art does not disclose or suggest the use of resin metal complex catalysts in vapor phase Fischer-Tropsch reactions. One skilled in this art would readily realize or assume that resins, particularly polystyrene resins would not hold up at the temperatures at which vapor phase Fischer-Tropsch reactions are conducted. See Catalysis, J. R. Anderson and M. Boudant, Eds. Chapter 4; Springer Verlag (1981). Specifically, the catalyst of the present invention operates in a temperature range from 175.degree. to 275.degree. C.
Synthesis gas is a mixture of carbon monoxide and hydrogen and can be produced by the gasification of coal with steam and oxygen. A description of conventional methods of coal gasification is provided in McGraw-Hill Encyclopedia of Science & Technology, 1977 Edition, Vol. 3, pages 248-249 (McGraw-Hill Book Company, New York).
Production of methane and higher hydrocarbons from coal by the Fischer-Tropsch reaction typically employs a group VIII catalyst (e.g. Fe, Co and Ni) at temperatures in the range of about 200.degree.-350.degree. C. and pressures in the range of about 2100-3500 kPa (300-500 psi).
While these processes are successful in making synthetic natural gas or oxygenated hydrocarbons, the operating conditions leave considerable room for improvement. The relatively severe operating conditions require high capital investment and power or energy consumption. In addition, the severe conditions present many operating problems. Accordingly, a catalyst which overcomes these disadvantages of the prior art processes is to be highly commended.
The present invention provides complexes useful as catalysts which enable Fischer-Tropsch synthesis to be achieved at mild operating temperatures and pressures.